This invention relates to actin-binding polypeptides called "supervillin" polypeptides, and nucleic acids encoding supervillin polypeptides.
Interactions between the plasma membrane and the actin cytoskeleton are mediated by actin-binding proteins associated with the plasma membrane. These actin-binding proteins are involved in a variety of processes, e.g., controlling cell shape, mediating cell-substrate and cell-cell interactions, organizing membrane proteins into domains, and in regulating membrane domain function. For example, some protein domains contain membrane-spanning proteins, such as ion channels and adhesion molecules, that are localized due to interactions with cortical meshworks of actin filaments cross-linked by spectrin. As another example, intercellular adhesion at adherens junctions, which is mediated by Ca.sup.2+ -sensitive transmembrane proteins called cadherins, depends upon cadherin attachment to actin filaments through linker proteins, such as .alpha.-catenin and .beta.-catenin.